So basically, Fairyland is an infinite plain, constantly expanding, with infinite diversity of terrain and populated by numerous fantasy creatures. Faeries breed like rabbits, though that's just a background element, and things like technology and clothing are a foreign concept.

Everything that isn't a child in Fairyland exist in a state of youthful adulthood. Child Faeries cocoon as infants, emerging looking as they would have if they were human children on their eighth birthday. After that they grow up as slow or fast as they please, and have access to various instinctive reality warping magics, like shapeshifting and the ability to travel through time in the human world.